The present invention relates to bone screws for osteosynthesis devices, for example spinal osteosynthesis devices, and more particularly to an improved bone screw and method for making the same.
Screws are known in the art which have a cylindro-conical shank extending from a head. The shank has a profile that includes a cylindrical portion and a conical portion. The thread on the shank of the screw defines a crest that becomes progressively flat in the conical portion of the shank. Consequently, the part of the thread with a truncated crest that is flat does not perform its bone anchorage function effectively, which may have an adverse effect on the fixation of the screw in porous bone or bone of poor quality. Thus, it is desirable to keep a cutting crest throughout the length of the thread in order to ensure proper bone anchorage.
The present invention is directed towards meeting this and other needs and to provide further benefits and advantages.